The present invention is related to a method for manufacturing a semiconductor device. For example, the present invention may be related to a method for manufacturing a high-k metal gate (HKMG) semiconductor device, i.e., a semiconductor device that includes a high-k member (with a dielectric constant higher than the dielectric constant of silicon dioxide or 2.5) and a metal gate member.
Manufacturing of an HKMG semiconductor device may involve minimization of oxygen diffusion and removal of a polysilicon dummy gate. For minimizing oxygen diffusion, spacers (e.g., offset spacers) in the device may be formed of silicon nitride (SiN). Nevertheless, chemicals used and/or generated during processing of the SiN spacers may substantially obstruct the removal of the polysilicon dummy gate and/or may cause an undesirable trapezoidal profile of a space for receiving metal gate material. The trapezoidal profile may undesirably affect the filling of the metal gate material and formation of the metal gate member. For example, unwanted voids may be formed in the metal gate member. As a result, the quality of the HKMG semiconductor device and/or the associated manufacturing yield may be undesirable.